diff --git a/imageapi_optimize.module b/imageapi_optimize.module
index 5ffeafd..31778ca 100644
--- a/imageapi_optimize.module
+++ b/imageapi_optimize.module
@@ -49,6 +49,15 @@ function imageapi_optimize_entity_type_alter(array &$entity_types) {
 }
 
 /**
+ * Implements hook_config_schema_info_alter().
+ */
+function imageapi_optimize_config_schema_info_alter(&$definitions) {
+  if (isset($definitions['image.style.*'])) {
+    $definitions['image.style.*']['mapping']['pipeline']['type'] = 'string';
+  }
+}
+
+/**
  * Implements hook_form_FORM_ID_alter().
  */
 function imageapi_optimize_form_image_style_edit_form_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state, $form_id) {
diff --git a/tests/modules/image_module_test/config/schema/image_module_test.schema.yml b/tests/modules/image_module_test/config/schema/image_module_test.schema.yml
new file mode 100644
index 0000000..9158f56
--- /dev/null
+++ b/tests/modules/image_module_test/config/schema/image_module_test.schema.yml
@@ -0,0 +1,15 @@
+image.effect.image_module_test_ajax:
+  type: mapping
+  label: 'Ajax test'
+  mapping:
+    test_parameter:
+      type: integer
+      label: 'Test Parameter'
+
+image.style.*.third_party.image_module_test:
+  type: mapping
+  label: 'Schema for image_module_test module additions to image_style entity'
+  mapping:
+    foo:
+      type: string
+      label: 'Label for foo'
diff --git a/tests/modules/image_module_test/image_module_test.info.yml b/tests/modules/image_module_test/image_module_test.info.yml
new file mode 100644
index 0000000..a50c463
--- /dev/null
+++ b/tests/modules/image_module_test/image_module_test.info.yml
@@ -0,0 +1,12 @@
+name: 'Image test'
+type: module
+description: 'Provides hook implementations for testing Image module functionality.'
+package: Testing
+# version: VERSION
+# core: 8.x
+
+# Information added by Drupal.org packaging script on 2016-09-21
+version: '8.2.0-rc2'
+core: '8.x'
+project: 'drupal'
+datestamp: 1474485575
diff --git a/tests/modules/image_module_test/image_module_test.module b/tests/modules/image_module_test/image_module_test.module
new file mode 100644
index 0000000..df71375
--- /dev/null
+++ b/tests/modules/image_module_test/image_module_test.module
@@ -0,0 +1,34 @@
+<?php
+
+/**
+ * @file
+ * Provides Image module hook implementations for testing purposes.
+ */
+
+use Drupal\image\ImageStyleInterface;
+
+function image_module_test_file_download($uri) {
+  $default_uri = \Drupal::state()->get('image.test_file_download') ?: FALSE;
+  if ($default_uri == $uri) {
+    return array('X-Image-Owned-By' => 'image_module_test');
+  }
+}
+
+/**
+ * Implements hook_image_effect_info_alter().
+ *
+ * Used to keep a count of cache misses in \Drupal\image\ImageEffectManager.
+ */
+function image_module_test_image_effect_info_alter(&$effects) {
+  $image_effects_definition_called = &drupal_static(__FUNCTION__, 0);
+  $image_effects_definition_called++;
+}
+
+/**
+ * Implements hook_image_style_presave().
+ *
+ * Used to save test third party settings in the image style entity.
+ */
+function image_module_test_image_style_presave(ImageStyleInterface $style) {
+  $style->setThirdPartySetting('image_module_test', 'foo', 'bar');
+}
diff --git a/tests/modules/image_module_test/src/Plugin/ImageEffect/AjaxTestImageEffect.php b/tests/modules/image_module_test/src/Plugin/ImageEffect/AjaxTestImageEffect.php
new file mode 100644
index 0000000..a18c263
--- /dev/null
+++ b/tests/modules/image_module_test/src/Plugin/ImageEffect/AjaxTestImageEffect.php
@@ -0,0 +1,84 @@
+<?php
+
+namespace Drupal\image_module_test\Plugin\ImageEffect;
+
+use Drupal\Core\Ajax\AjaxResponse;
+use Drupal\Core\Ajax\HtmlCommand;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Image\ImageInterface;
+use Drupal\image\ConfigurableImageEffectBase;
+
+/**
+ * Provides a test effect using Ajax in the configuration form.
+ *
+ * @ImageEffect(
+ *   id = "image_module_test_ajax",
+ *   label = @Translation("Ajax test")
+ * )
+ */
+class AjaxTestImageEffect extends ConfigurableImageEffectBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function defaultConfiguration() {
+    return [
+      'test_parameter' => 0,
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
+    $form['test_parameter'] = [
+      '#type' => 'number',
+      '#title' => t('Test parameter'),
+      '#default_value' => $this->configuration['test_parameter'],
+      '#min' => 0,
+    ];
+    $form['ajax_refresh'] = [
+      '#type' => 'button',
+      '#value' => $this->t('Ajax refresh'),
+      '#ajax' => ['callback' => [$this, 'ajaxCallback']],
+    ];
+    $form['ajax_value'] = [
+      '#id' => 'ajax-value',
+      '#type' => 'item',
+      '#title' => $this->t('Ajax value'),
+      '#markup' => 'bar',
+    ];
+    return $form;
+  }
+
+  /**
+   * AJAX callback.
+   */
+  public function ajaxCallback($form, FormStateInterface $form_state) {
+    $item = [
+      '#type' => 'item',
+      '#title' => $this->t('Ajax value'),
+      '#markup' => microtime(),
+    ];
+    $response = new AjaxResponse();
+    $response->addCommand(new HtmlCommand('#ajax-value', $item));
+    return $response;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitConfigurationForm(array &$form, FormStateInterface $form_state) {
+    parent::submitConfigurationForm($form, $form_state);
+
+    $this->configuration['test_parameter'] = $form_state->getValue('test_parameter');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function applyEffect(ImageInterface $image) {
+    return TRUE;
+  }
+
+}
diff --git a/tests/modules/image_module_test/src/Plugin/ImageEffect/NullTestImageEffect.php b/tests/modules/image_module_test/src/Plugin/ImageEffect/NullTestImageEffect.php
new file mode 100644
index 0000000..ceca6fa
--- /dev/null
+++ b/tests/modules/image_module_test/src/Plugin/ImageEffect/NullTestImageEffect.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace Drupal\image_module_test\Plugin\ImageEffect;
+
+use Drupal\Core\Image\ImageInterface;
+use Drupal\image\ImageEffectBase;
+
+/**
+ * Performs no operation on an image resource.
+ *
+ * @ImageEffect(
+ *   id = "image_module_test_null",
+ *   label = @Translation("Image module test")
+ * )
+ */
+class NullTestImageEffect extends ImageEffectBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function transformDimensions(array &$dimensions, $uri) {
+    // Unset image dimensions.
+    $dimensions['width'] = $dimensions['height'] = NULL;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function applyEffect(ImageInterface $image) {
+    return TRUE;
+  }
+
+}
diff --git a/tests/modules/image_module_test/src/Plugin/ImageEffect/UriDependentTestImageEffect.php b/tests/modules/image_module_test/src/Plugin/ImageEffect/UriDependentTestImageEffect.php
new file mode 100644
index 0000000..5e5ddc7
--- /dev/null
+++ b/tests/modules/image_module_test/src/Plugin/ImageEffect/UriDependentTestImageEffect.php
@@ -0,0 +1,64 @@
+<?php
+
+namespace Drupal\image_module_test\Plugin\ImageEffect;
+
+use Drupal\Core\Image\ImageInterface;
+use Drupal\image\ImageEffectBase;
+
+/**
+ * Performs an image operation that depends on the URI of the original image.
+ *
+ * @ImageEffect(
+ *   id = "image_module_test_uri_dependent",
+ *   label = @Translation("URI dependent test image effect")
+ * )
+ */
+class UriDependentTestImageEffect extends ImageEffectBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function transformDimensions(array &$dimensions, $uri) {
+    $dimensions = $this->getUriDependentDimensions($uri);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function applyEffect(ImageInterface $image) {
+    $dimensions = $this->getUriDependentDimensions($image->getSource());
+    return $image->resize($dimensions['width'], $dimensions['height']);
+  }
+
+  /**
+   * Make the image dimensions dependent on the image file extension.
+   *
+   * @param string $uri
+   *   Original image file URI.
+   *
+   * @return array
+   *   Associative array.
+   *   - width: Integer with the derivative image width.
+   *   - height: Integer with the derivative image height.
+   */
+  protected function getUriDependentDimensions($uri) {
+    $dimensions = [];
+    $extension = pathinfo($uri, PATHINFO_EXTENSION);
+    switch (strtolower($extension)) {
+      case 'png':
+        $dimensions['width'] = $dimensions['height'] = 100;
+        break;
+
+      case 'gif':
+        $dimensions['width'] = $dimensions['height'] = 50;
+        break;
+
+      default:
+        $dimensions['width'] = $dimensions['height'] = 20;
+        break;
+
+    }
+    return $dimensions;
+  }
+
+}
diff --git a/tests/modules/image_test_views/image_test_views.info.yml b/tests/modules/image_test_views/image_test_views.info.yml
new file mode 100644
index 0000000..b029410
--- /dev/null
+++ b/tests/modules/image_test_views/image_test_views.info.yml
@@ -0,0 +1,15 @@
+name: 'Image test views'
+type: module
+description: 'Provides default views for views image tests.'
+package: Testing
+# version: VERSION
+# core: 8.x
+dependencies:
+  - image
+  - views
+
+# Information added by Drupal.org packaging script on 2016-09-21
+version: '8.2.0-rc2'
+core: '8.x'
+project: 'drupal'
+datestamp: 1474485575
diff --git a/tests/modules/image_test_views/test_views/views.view.test_image_user_image_data.yml b/tests/modules/image_test_views/test_views/views.view.test_image_user_image_data.yml
new file mode 100644
index 0000000..8ea166b
--- /dev/null
+++ b/tests/modules/image_test_views/test_views/views.view.test_image_user_image_data.yml
@@ -0,0 +1,77 @@
+langcode: en
+status: true
+dependencies:
+  module:
+    - file
+    - user
+id: test_image_user_image_data
+label: test_image_user_image_data
+module: views
+description: ''
+tag: ''
+base_table: users_field_data
+base_field: uid
+core: 8.x
+display:
+  default:
+    display_plugin: default
+    id: default
+    display_title: Master
+    position: 0
+    display_options:
+      access:
+        type: perm
+        options:
+          perm: 'access user profiles'
+      cache:
+        type: tag
+      style:
+        type: table
+        options:
+          grouping: {  }
+          row_class: ''
+          default_row_class: true
+          override: true
+          sticky: false
+          caption: ''
+          summary: ''
+          description: ''
+          columns:
+            name: name
+            fid: fid
+          info:
+            name:
+              sortable: false
+              default_sort_order: asc
+              align: ''
+              separator: ''
+              empty_column: false
+              responsive: ''
+            fid:
+              sortable: false
+              default_sort_order: asc
+              align: ''
+              separator: ''
+              empty_column: false
+              responsive: ''
+          default: '-1'
+          empty_table: false
+      row:
+        type: fields
+        options:
+          inline: {  }
+          separator: ''
+          hide_empty: false
+          default_field_elements: true
+      relationships:
+        user_picture_target_id:
+          id: user_picture_target_id
+          table: user__user_picture
+          field: user_picture_target_id
+          relationship: none
+          group_type: group
+          admin_label: 'image from user_picture'
+          required: true
+          plugin_id: standard
+      arguments: {  }
+      display_extenders: {  }
diff --git a/tests/src/Kernel/ImageFormatterTest.php b/tests/src/Kernel/ImageFormatterTest.php
new file mode 100644
index 0000000..04ac8b0
--- /dev/null
+++ b/tests/src/Kernel/ImageFormatterTest.php
@@ -0,0 +1,102 @@
+<?php
+
+namespace Drupal\Tests\imageapi_optimize\Kernel;
+
+use Drupal\Component\Utility\Unicode;
+use Drupal\Core\Field\FieldStorageDefinitionInterface;
+use Drupal\entity_test\Entity\EntityTest;
+use Drupal\field\Entity\FieldConfig;
+use Drupal\field\Entity\FieldStorageConfig;
+use Drupal\Tests\field\Kernel\FieldKernelTestBase;
+
+/**
+ * Tests the image field rendering using entity fields of the image field type.
+ *
+ * @group image
+ */
+class ImageFormatterTest extends FieldKernelTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('file', 'image', 'imageapi_optimize');
+
+  /**
+   * @var string
+   */
+  protected $entityType;
+
+  /**
+   * @var string
+   */
+  protected $bundle;
+
+  /**
+   * @var string
+   */
+  protected $fieldName;
+
+  /**
+   * @var \Drupal\Core\Entity\Display\EntityViewDisplayInterface
+   */
+  protected $display;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    $this->installConfig(['field']);
+    $this->installEntitySchema('entity_test');
+    $this->installEntitySchema('file');
+    $this->installSchema('file', array('file_usage'));
+
+    $this->entityType = 'entity_test';
+    $this->bundle = $this->entityType;
+    $this->fieldName = Unicode::strtolower($this->randomMachineName());
+
+    FieldStorageConfig::create(array(
+      'entity_type' => $this->entityType,
+      'field_name' => $this->fieldName,
+      'type' => 'image',
+      'cardinality' => FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED,
+    ))->save();
+    FieldConfig::create([
+      'entity_type' => $this->entityType,
+      'field_name' => $this->fieldName,
+      'bundle' => $this->bundle,
+      'settings' => [
+        'file_extensions' => 'jpg',
+      ],
+    ])->save();
+
+    $this->display = entity_get_display($this->entityType, $this->bundle, 'default')
+      ->setComponent($this->fieldName, [
+        'type' => 'image',
+        'label' => 'hidden',
+      ]);
+    $this->display->save();
+  }
+
+  /**
+   * Tests the cache tags from image formatters.
+   */
+  function testImageFormatterCacheTags() {
+    // Create a test entity with the image field set.
+    $entity = EntityTest::create([
+      'name' => $this->randomMachineName(),
+    ]);
+    $entity->{$this->fieldName}->generateSampleItems(2);
+    $entity->save();
+
+    // Generate the render array to verify if the cache tags are as expected.
+    $build = $this->display->build($entity);
+
+    $this->assertEquals($entity->{$this->fieldName}[0]->entity->getCacheTags(), $build[$this->fieldName][0]['#cache']['tags'], 'First image cache tags is as expected');
+    $this->assertEquals($entity->{$this->fieldName}[1]->entity->getCacheTags(), $build[$this->fieldName][1]['#cache']['tags'], 'Second image cache tags is as expected');
+  }
+
+}
diff --git a/tests/src/Kernel/ImageImportTest.php b/tests/src/Kernel/ImageImportTest.php
new file mode 100644
index 0000000..d8ca036
--- /dev/null
+++ b/tests/src/Kernel/ImageImportTest.php
@@ -0,0 +1,46 @@
+<?php
+
+namespace Drupal\Tests\imageapi_optimize\Kernel;
+
+use Drupal\image\Entity\ImageStyle;
+use Drupal\KernelTests\KernelTestBase;
+
+/**
+ * Tests config import for Image styles.
+ *
+ * @group image
+ */
+class ImageImportTest extends KernelTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['system', 'image', 'image_module_test', 'imageapi_optimize'];
+
+  /**
+   * Tests importing image styles.
+   */
+  public function testImport() {
+    $style = ImageStyle::create([
+      'name' => 'test'
+    ]);
+
+    $style->addImageEffect(['id' => 'image_module_test_null']);
+    $style->addImageEffect(['id' => 'image_module_test_null']);
+    $style->save();
+
+    $this->assertEqual(count($style->getEffects()), 2);
+
+    $uuid = \Drupal::service('uuid')->generate();
+    $style->set('effects', [
+      $uuid => [
+        'id' => 'image_module_test_null',
+      ],
+    ]);
+    $style->save();
+
+    $style = ImageStyle::load('test');
+    $this->assertEqual(count($style->getEffects()), 1);
+  }
+
+}
diff --git a/tests/src/Kernel/ImageItemTest.php b/tests/src/Kernel/ImageItemTest.php
new file mode 100644
index 0000000..1e04c26
--- /dev/null
+++ b/tests/src/Kernel/ImageItemTest.php
@@ -0,0 +1,132 @@
+<?php
+
+namespace Drupal\Tests\imageapi_optimize\Kernel;
+
+use Drupal\Core\Field\FieldItemInterface;
+use Drupal\Core\Field\FieldItemListInterface;
+use Drupal\Core\Field\FieldStorageDefinitionInterface;
+use Drupal\entity_test\Entity\EntityTest;
+use Drupal\field\Entity\FieldConfig;
+use Drupal\Tests\field\Kernel\FieldKernelTestBase;
+use Drupal\field\Entity\FieldStorageConfig;
+use Drupal\file\Entity\File;
+
+/**
+ * Tests using entity fields of the image field type.
+ *
+ * @group image
+ */
+class ImageItemTest extends FieldKernelTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('file', 'image', 'imageapi_optimize');
+
+  /**
+   * Created file entity.
+   *
+   * @var \Drupal\file\Entity\File
+   */
+  protected $image;
+
+  /**
+   * @var \Drupal\Core\Image\ImageFactory
+   */
+  protected $imageFactory;
+
+  protected function setUp() {
+    parent::setUp();
+
+    $this->installEntitySchema('file');
+    $this->installSchema('file', array('file_usage'));
+
+    FieldStorageConfig::create(array(
+      'entity_type' => 'entity_test',
+      'field_name' => 'image_test',
+      'type' => 'image',
+      'cardinality' => FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED,
+    ))->save();
+    FieldConfig::create([
+      'entity_type' => 'entity_test',
+      'field_name' => 'image_test',
+      'bundle' => 'entity_test',
+      'settings' => [
+        'file_extensions' => 'jpg',
+      ],
+    ])->save();
+    file_unmanaged_copy(\Drupal::root() . '/core/misc/druplicon.png', 'public://example.jpg');
+    $this->image = File::create([
+      'uri' => 'public://example.jpg',
+    ]);
+    $this->image->save();
+    $this->imageFactory = $this->container->get('image.factory');
+  }
+
+  /**
+   * Tests using entity fields of the image field type.
+   */
+  public function testImageItem() {
+    // Create a test entity with the image field set.
+    $entity = EntityTest::create();
+    $entity->image_test->target_id = $this->image->id();
+    $entity->image_test->alt = $alt = $this->randomMachineName();
+    $entity->image_test->title = $title = $this->randomMachineName();
+    $entity->name->value = $this->randomMachineName();
+    $entity->save();
+
+    $entity = EntityTest::load($entity->id());
+    $this->assertTrue($entity->image_test instanceof FieldItemListInterface, 'Field implements interface.');
+    $this->assertTrue($entity->image_test[0] instanceof FieldItemInterface, 'Field item implements interface.');
+    $this->assertEqual($entity->image_test->target_id, $this->image->id());
+    $this->assertEqual($entity->image_test->alt, $alt);
+    $this->assertEqual($entity->image_test->title, $title);
+    $image = $this->imageFactory->get('public://example.jpg');
+    $this->assertEqual($entity->image_test->width, $image->getWidth());
+    $this->assertEqual($entity->image_test->height, $image->getHeight());
+    $this->assertEqual($entity->image_test->entity->id(), $this->image->id());
+    $this->assertEqual($entity->image_test->entity->uuid(), $this->image->uuid());
+
+    // Make sure the computed entity reflects updates to the referenced file.
+    file_unmanaged_copy(\Drupal::root() . '/core/misc/druplicon.png', 'public://example-2.jpg');
+    $image2 = File::create([
+      'uri' => 'public://example-2.jpg',
+    ]);
+    $image2->save();
+
+    $entity->image_test->target_id = $image2->id();
+    $entity->image_test->alt = $new_alt = $this->randomMachineName();
+    // The width and height is only updated when width is not set.
+    $entity->image_test->width = NULL;
+    $entity->save();
+    $this->assertEqual($entity->image_test->entity->id(), $image2->id());
+    $this->assertEqual($entity->image_test->entity->getFileUri(), $image2->getFileUri());
+    $image = $this->imageFactory->get('public://example-2.jpg');
+    $this->assertEqual($entity->image_test->width, $image->getWidth());
+    $this->assertEqual($entity->image_test->height, $image->getHeight());
+    $this->assertEqual($entity->image_test->alt, $new_alt);
+
+    // Check that the image item can be set to the referenced file directly.
+    $entity->image_test = $this->image;
+    $this->assertEqual($entity->image_test->target_id, $this->image->id());
+
+    // Delete the image and try to save the entity again.
+    $this->image->delete();
+    $entity = EntityTest::create(array('mame' => $this->randomMachineName()));
+    $entity->save();
+
+    // Test image item properties.
+    $expected = array('target_id', 'entity', 'alt', 'title', 'width', 'height');
+    $properties = $entity->getFieldDefinition('image_test')->getFieldStorageDefinition()->getPropertyDefinitions();
+    $this->assertEqual(array_keys($properties), $expected);
+
+    // Test the generateSampleValue() method.
+    $entity = EntityTest::create();
+    $entity->image_test->generateSampleItems();
+    $this->entityValidateAndSave($entity);
+    $this->assertEqual($entity->image_test->entity->get('filemime')->value, 'image/jpeg');
+  }
+
+}
diff --git a/tests/src/Kernel/ImageStyleCustomStreamWrappersTest.php b/tests/src/Kernel/ImageStyleCustomStreamWrappersTest.php
new file mode 100644
index 0000000..4d12713
--- /dev/null
+++ b/tests/src/Kernel/ImageStyleCustomStreamWrappersTest.php
@@ -0,0 +1,111 @@
+<?php
+
+namespace Drupal\Tests\imageapi_optimize\Kernel;
+
+use Drupal\Core\DependencyInjection\ContainerBuilder;
+use Drupal\Core\StreamWrapper\PrivateStream;
+use Drupal\Core\StreamWrapper\PublicStream;
+use Drupal\file_test\StreamWrapper\DummyReadOnlyStreamWrapper;
+use Drupal\file_test\StreamWrapper\DummyRemoteReadOnlyStreamWrapper;
+use Drupal\file_test\StreamWrapper\DummyStreamWrapper;
+use Drupal\image\Entity\ImageStyle;
+use Drupal\KernelTests\KernelTestBase;
+
+/**
+ * Tests derivative generation with source images using stream wrappers.
+ *
+ * @group image
+ */
+class ImageStyleCustomStreamWrappersTest extends KernelTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var string[]
+   */
+  public static $modules = ['system', 'image', 'imageapi_optimize'];
+
+  /**
+   * A testing image style entity.
+   *
+   * @var \Drupal\image\ImageStyleInterface
+   */
+  protected $imageStyle;
+
+  /**
+   * The file system service.
+   *
+   * @var \Drupal\Core\File\FileSystemInterface
+   */
+  protected $fileSystem;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+    $this->fileSystem = $this->container->get('file_system');
+    $this->config('system.file')->set('default_scheme', 'public')->save();
+    $this->imageStyle = ImageStyle::create(['name' => 'test']);
+    $this->imageStyle->save();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function register(ContainerBuilder $container) {
+    parent::register($container);
+    foreach ($this->providerTestCustomStreamWrappers() as $stream_wrapper) {
+      $scheme = $stream_wrapper[0];
+      $class = $stream_wrapper[2];
+      $container->register("stream_wrapper.$scheme", $class)
+        ->addTag('stream_wrapper', ['scheme' => $scheme]);
+    }
+  }
+
+  /**
+   * Tests derivative creation with several source on a local writable stream.
+   *
+   * @dataProvider providerTestCustomStreamWrappers
+   *
+   * @param string $source_scheme
+   *   The source stream wrapper scheme.
+   * @param string $expected_scheme
+   *   The derivative expected stream wrapper scheme.
+   */
+  public function testCustomStreamWrappers($source_scheme, $expected_scheme) {
+    $derivative_uri = $this->imageStyle->buildUri("$source_scheme://some/path/image.png");
+    $derivative_scheme = $this->fileSystem->uriScheme($derivative_uri);
+
+    // Check that the derivative scheme is the expected scheme.
+    $this->assertSame($expected_scheme, $derivative_scheme);
+
+    // Check that the derivative URI is the expected one.
+    $expected_uri = "$expected_scheme://styles/{$this->imageStyle->id()}/$source_scheme/some/path/image.png";
+    $this->assertSame($expected_uri, $derivative_uri);
+  }
+
+  /**
+   * Provide test cases for testCustomStreamWrappers().
+   *
+   * Derivatives created from writable source stream wrappers will inherit the
+   * scheme from source. Derivatives created from read-only stream wrappers will
+   * fall-back to the default scheme.
+   *
+   * @return array[]
+   *   An array having each element an array with three items:
+   *   - The source stream wrapper scheme.
+   *   - The derivative expected stream wrapper scheme.
+   *   - The stream wrapper service class.
+   */
+  public function providerTestCustomStreamWrappers() {
+    return [
+      ['public', 'public', PublicStream::class],
+      ['private', 'private', PrivateStream::class],
+      ['dummy', 'dummy', DummyStreamWrapper::class],
+      ['dummy-readonly', 'public', DummyReadOnlyStreamWrapper::class],
+      ['dummy-remote-readonly', 'public', DummyRemoteReadOnlyStreamWrapper::class],
+    ];
+  }
+
+}
diff --git a/tests/src/Kernel/ImageStyleIntegrationTest.php b/tests/src/Kernel/ImageStyleIntegrationTest.php
new file mode 100644
index 0000000..aee8c33
--- /dev/null
+++ b/tests/src/Kernel/ImageStyleIntegrationTest.php
@@ -0,0 +1,112 @@
+<?php
+
+namespace Drupal\Tests\imageapi_optimize\Kernel;
+
+use Drupal\Core\Entity\Entity\EntityFormDisplay;
+use Drupal\Core\Entity\Entity\EntityViewDisplay;
+use Drupal\field\Entity\FieldConfig;
+use Drupal\field\Entity\FieldStorageConfig;
+use Drupal\image\Entity\ImageStyle;
+use Drupal\KernelTests\KernelTestBase;
+use Drupal\node\Entity\NodeType;
+
+/**
+ * Tests the integration of ImageStyle with the core.
+ *
+ * @group image
+ */
+class ImageStyleIntegrationTest extends KernelTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['image', 'file', 'field', 'system', 'user', 'node', 'imageapi_optimize'];
+
+  /**
+   * Tests the dependency between ImageStyle and entity display components.
+   */
+  public function testEntityDisplayDependency() {
+    // Create two image styles.
+    /** @var \Drupal\image\ImageStyleInterface $style */
+    $style = ImageStyle::create(['name' => 'main_style']);
+    $style->save();
+    /** @var \Drupal\image\ImageStyleInterface $replacement */
+    $replacement = ImageStyle::create(['name' => 'replacement_style']);
+    $replacement->save();
+
+    // Create a node-type, named 'note'.
+    $node_type = NodeType::create(['type' => 'note']);
+    $node_type->save();
+
+    // Create an image field and attach it to the 'note' node-type.
+    FieldStorageConfig::create([
+      'entity_type' => 'node',
+      'field_name' => 'sticker',
+      'type' => 'image',
+    ])->save();
+    FieldConfig::create([
+      'entity_type' => 'node',
+      'field_name' => 'sticker',
+      'bundle' => 'note',
+    ])->save();
+
+    // Create the default entity view display and set the 'sticker' field to use
+    // the 'main_style' images style in formatter.
+    /** @var \Drupal\Core\Entity\Display\EntityViewDisplayInterface $view_display */
+    $view_display = EntityViewDisplay::create([
+      'targetEntityType' => 'node',
+      'bundle' => 'note',
+      'mode' => 'default',
+      'status' => TRUE,
+    ])->setComponent('sticker', ['settings' => ['image_style' => 'main_style']]);
+    $view_display->save();
+
+    // Create the default entity form display and set the 'sticker' field to use
+    // the 'main_style' images style in the widget.
+    /** @var \Drupal\Core\Entity\Display\EntityFormDisplayInterface $form_display */
+    $form_display = EntityFormDisplay::create([
+      'targetEntityType' => 'node',
+      'bundle' => 'note',
+      'mode' => 'default',
+      'status' => TRUE,
+    ])->setComponent('sticker', ['settings' => ['preview_image_style' => 'main_style']]);
+    $form_display->save();
+
+    // Check that the entity displays exists before dependency removal.
+    $this->assertNotNull(EntityViewDisplay::load($view_display->id()));
+    $this->assertNotNull(EntityFormDisplay::load($form_display->id()));
+
+    // Delete the 'main_style' image style. Before that, emulate the UI process
+    // of selecting a replacement style by setting the replacement image style
+    // ID in the image style storage.
+    /** @var \Drupal\image\ImageStyleStorageInterface $storage */
+    $storage = $this->container->get('entity.manager')->getStorage($style->getEntityTypeId());
+    $storage->setReplacementId('main_style', 'replacement_style');
+    $style->delete();
+
+    // Check that the entity displays exists after dependency removal.
+    $this->assertNotNull($view_display = EntityViewDisplay::load($view_display->id()));
+    $this->assertNotNull($form_display = EntityFormDisplay::load($form_display->id()));
+    // Check that the 'sticker' formatter component exists in both displays.
+    $this->assertNotNull($formatter = $view_display->getComponent('sticker'));
+    $this->assertNotNull($widget = $form_display->getComponent('sticker'));
+    // Check that both displays are using now 'replacement_style' for images.
+    $this->assertSame('replacement_style', $formatter['settings']['image_style']);
+    $this->assertSame('replacement_style', $widget['settings']['preview_image_style']);
+
+    // Delete the 'replacement_style' without setting a replacement image style.
+    $replacement->delete();
+
+    // The entity view and form displays exists after dependency removal.
+    $this->assertNotNull($view_display = EntityViewDisplay::load($view_display->id()));
+    $this->assertNotNull($form_display = EntityFormDisplay::load($form_display->id()));
+    // The 'sticker' formatter component should be hidden in view display.
+    $this->assertNull($view_display->getComponent('sticker'));
+    $this->assertTrue($view_display->get('hidden')['sticker']);
+    // The 'sticker' widget component should be active in form displays, but the
+    // image preview should be disabled.
+    $this->assertNotNull($widget = $form_display->getComponent('sticker'));
+    $this->assertSame('', $widget['settings']['preview_image_style']);
+  }
+
+}
diff --git a/tests/src/Kernel/Views/ImageViewsDataTest.php b/tests/src/Kernel/Views/ImageViewsDataTest.php
new file mode 100644
index 0000000..70bfd84
--- /dev/null
+++ b/tests/src/Kernel/Views/ImageViewsDataTest.php
@@ -0,0 +1,92 @@
+<?php
+
+namespace Drupal\Tests\imageapi_optimize\Kernel\Views;
+
+use Drupal\field\Entity\FieldStorageConfig;
+use Drupal\field\Entity\FieldConfig;
+use Drupal\Tests\views\Kernel\ViewsKernelTestBase;
+use Drupal\views\Views;
+
+/**
+ * Tests image views data.
+ *
+ * @group image
+ */
+class ImageViewsDataTest extends ViewsKernelTestBase {
+
+  /**
+   * Modules to install.
+   *
+   * @var array
+   */
+  public static $modules = array('image', 'file', 'views', 'entity_test', 'user', 'field', 'imageapi_optimize');
+
+  /**
+   * Tests views data generated for image field relationship.
+   *
+   * @see image_field_views_data()
+   * @see image_field_views_data_views_data_alter()
+   */
+  public function testRelationshipViewsData() {
+    // Create image field to entity_test.
+    FieldStorageConfig::create(array(
+      'entity_type' => 'entity_test',
+      'field_name' => 'field_base_image',
+      'type' => 'image',
+    ))->save();
+    FieldConfig::create(array(
+      'entity_type' => 'entity_test',
+      'field_name' => 'field_base_image',
+      'bundle' => 'entity_test',
+    ))->save();
+    // Check the generated views data.
+    $views_data = Views::viewsData()->get('entity_test__field_base_image');
+    $relationship = $views_data['field_base_image_target_id']['relationship'];
+    $this->assertEqual($relationship['id'], 'standard');
+    $this->assertEqual($relationship['base'], 'file_managed');
+    $this->assertEqual($relationship['base field'], 'fid');
+    $this->assertEqual($relationship['entity type'], 'file');
+    // Check the backwards reference.
+    $views_data = Views::viewsData()->get('file_managed');
+    $relationship = $views_data['reverse_field_base_image_entity_test']['relationship'];
+    $this->assertEqual($relationship['id'], 'entity_reverse');
+    $this->assertEqual($relationship['base'], 'entity_test');
+    $this->assertEqual($relationship['base field'], 'id');
+    $this->assertEqual($relationship['field table'], 'entity_test__field_base_image');
+    $this->assertEqual($relationship['field field'], 'field_base_image_target_id');
+    $this->assertEqual($relationship['field_name'], 'field_base_image');
+    $this->assertEqual($relationship['entity_type'], 'entity_test');
+    $this->assertEqual($relationship['join_extra'][0], ['field' => 'deleted', 'value' => 0, 'numeric' => TRUE]);
+
+    // Create image field to entity_test_mul.
+    FieldStorageConfig::create(array(
+      'entity_type' => 'entity_test_mul',
+      'field_name' => 'field_data_image',
+      'type' => 'image',
+    ))->save();
+    FieldConfig::create(array(
+      'entity_type' => 'entity_test_mul',
+      'field_name' => 'field_data_image',
+      'bundle' => 'entity_test_mul',
+    ))->save();
+    // Check the generated views data.
+    $views_data = Views::viewsData()->get('entity_test_mul__field_data_image');
+    $relationship = $views_data['field_data_image_target_id']['relationship'];
+    $this->assertEqual($relationship['id'], 'standard');
+    $this->assertEqual($relationship['base'], 'file_managed');
+    $this->assertEqual($relationship['base field'], 'fid');
+    $this->assertEqual($relationship['entity type'], 'file');
+    // Check the backwards reference.
+    $views_data = Views::viewsData()->get('file_managed');
+    $relationship = $views_data['reverse_field_data_image_entity_test_mul']['relationship'];
+    $this->assertEqual($relationship['id'], 'entity_reverse');
+    $this->assertEqual($relationship['base'], 'entity_test_mul_property_data');
+    $this->assertEqual($relationship['base field'], 'id');
+    $this->assertEqual($relationship['field table'], 'entity_test_mul__field_data_image');
+    $this->assertEqual($relationship['field field'], 'field_data_image_target_id');
+    $this->assertEqual($relationship['field_name'], 'field_data_image');
+    $this->assertEqual($relationship['entity_type'], 'entity_test_mul');
+    $this->assertEqual($relationship['join_extra'][0], ['field' => 'deleted', 'value' => 0, 'numeric' => TRUE]);
+  }
+
+}